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Vitamins are organic compounds necessary for normal growth,
maintenance of health, and reproduction. There are 13 vitamins
currently identified as essential for maintaining good health;
the body cannot survive without them.
Function
Vitamins help the body convert carbohydrates and fat into
energy and assist in the formation of bones and tissues. Vitamins
are either fat-soluble or water-soluble. Fat-soluble vitamins
cannot be dissolved in water, so they are stored in the body
fat until they are transported to the cells by the blood.
Because these vitamins can accumulate in the body, it is especially
important for a person’s regular daily nutrient intake
of fat soluble vitamins not to exceed the Tolerable Upper
Intake Levels (UL). Water-soluble vitamins are easily dissolved
by water and therefore are not significantly stored by the
body. Water-soluble vitamins must be replenished frequently.
Vitamins A, D, E, and K are the fat-soluble vitamins.
| Fat-Soluble
Vitamin
Alternative Names |
|
Description |
|
Sources |
Vitamin
A
Retinol
Beta-carotene (a precursor) |
|
Responsible for night
and color vision, growth of bones and teeth, immune function,
maintenance of epithelial tissues, and embryonic development.
Excessive amounts of certain forms of Vitamin A (found
in some skin medications) can cause fetal abnormalities. |
|
Dark green and dark yellow
vegetables, yellow fruits, egg yolks, whole milk, liver,
and fish oils. |
Vitamin D
Calciferol |
|
Important for the normal growth and development
of bones and teeth. Aids in the absorption and utilization
of calcium and phosphorus. With exposure to the sun, the
body is able to make its own Vitamin D. |
|
Egg yolks, liver, fish liver oils, fortified
cereals, and fortified milk. |
Vitamin
E
Tocopherol |
|
Protects cells from oxidation
and is important in cell membranes. Oxidation is a chemical
change that occurs as a result of exposure to oxygen.
When blood cells or tissue cells are exposed to oxygen,
the resulting chemical change causes a weakening of the
cell walls and thus damages the tissues. Vitamin E is
most effective in protecting the red blood cells in the
lungs and the cells of the lung tissue because of their
continuous exposure to oxygen. |
|
Vegetable oils, whole
grains, nuts and seeds, liver, fish oils, and green leafy
vegetables (spinach, kale, etc.). |
| Vitamin K |
|
Necessary for protein synthesis involved
in blood clotting and other body processes. |
|
Green vegetables (leafy vegetables, broccoli,
Brussels sprouts), cabbage, plant oils, margarine. Can
be produced by bacteria in the gastrointestinal tract. |
B1
Thiamin
Aneurin |
|
Helps the body breakdown
carbohydrates and release energy from food. It is necessary
for cell respiration, promotion of normal appetite and
digestion, and maintenance of a healthy nervous system.
Thiamin is heat sensitive and is easily leached into the
cooking liquid. |
|
Enriched or fortified
whole grain products, green leafy vegetables, legumes,
and pork.
|
B2
Riboflavin |
|
Important for the breakdown of foods and
the release of energy (oxidation-reduction reactions).
Riboflavin is easily destroyed by exposure to light, especially
sunlight. |
|
Fortified cereals and bread products, eggs,
fish, organ meats, and milk. |
B3
Niacin
Nicotinic acid |
|
Helps cells convert food
into energy, and is important in the nervous and digestive
systems. |
|
Lean meats, poultry, fish,
nuts, enriched or fortified bread products and cereals,
eggs, and dairy products. |
Folate
Folic acid
Folacin |
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Necessary for the body to produce normal
red blood cells and for amino acids and nucleic acid metabolism.
Key in preventing neural tube defects, such as spina bifida,
during pregnancy. |
|
Dark leafy green vegetables, enriched grain
and cereal products, yeast.
|
| Biotin |
|
Essential in the metabolism
of fats and amino acids. |
|
Liver and eggs are important
sources of biotin; it is also found in baker’s yeast,
and legumes. |
B5
Pantothenic acid |
|
Aids in the metabolism of fats and the
formation of cholesterol and hormones. |
|
Eggs, milk, whole-grain products, sweet
potatoes, and lean beef. |
B6
Pyridoxine |
|
Important in maintaining
nervous tissue function and muscle cells, DNA and RNA
production, and the metabolism of carbohydrates, proteins,
and fats. |
|
Sources include poultry,
fish, fortified whole grain cereals, and lentils. |
B12
Cobalamin
Cyanocobalamin |
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Important in red blood cell formation,
nucleic acid metabolism and the prevention of pernicious
anemia. |
|
Animal products (meat, fish, poultry, milk),
fortified cereals. |
Vitamin
C
Ascorbic acid |
|
Aids in the formation
of collagen, the healing of wounds, and the absorption
of iron and calcium. Vitamin C is also an important antioxidant. |
|
Sources include citrus
fruits, parsley, broccoli, green and red peppers, and
tomatoes. |
Research continues into the role vitamins and minerals play
in preventing chronic disease and in maintaining health and
wellness. The Dietary
Reference Intakes serve as guidelines
for determining the amounts of nutrients that a person needs
each day.
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